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BIOL 111 > Final - Part 3 > Flashcards

Final - Part 3 Flashcards

1
Q

17

What is the ultimate source of genetic variation?

A

MUTATION of nucleotide sequence

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2
Q

17

What does variation in a population mean?
What does success of an organism mean?

A

We think about genetic and phenotypic variation at the level of a population of the same species

success of an organism: measured by the # of offspring which are contributed to the next generation.

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3
Q

17

Fitness

Define it. But it’s not that important

A

Quatification of an individual’s genetic contribution to the next generation

It’s not all about how well it could survive

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4
Q

17

Toward Evolutionary theory
Jean-Baptist Lamarch + criticism

A
  • Proposed inheritance of acquired characteristics as a mechanism for species to change over time
  • Use it or lose it - repeated use of a trait changes and strengthen it (vice versa)
  • These strengthened & advantageous characteristics are passed on to offspring
  • For example, if a giraffe stretched its neck to reach leaves high up in trees, its offspring would inherit longer necks.
  • Criticism: how is that passed on genetically??
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5
Q

17

Charles Darwin

A
  • Gradient of Variation in appearances depending on the environment the species live in
  • Natural selection
  • There are variations in heritable traits within populations
  • Some variants are more successful and more able to reproduce than others in a given environment.
  • The popuation thus changes over time with respect to this trait.
  • Born with certain traits, not acquiring it.
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6
Q

17

Natural Selection

A

The more successful variants are thought of as being selected by its environment

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7
Q

17

3 Types of Selection from selective pressure

Which one is the most likely to form new species?

Draw diagrams

A
  1. Stabilizing selection - decreasing the range between the phenotypes to an average
  2. Directional selection - Going to 1 direction (white -> black moth)
  3. Diversifying selection - No in between, going to 2(or more) extreme ends
    - MOST likely to result in the formation of new species
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8
Q

17

Artificial selection

Example of it

A

Humans deliberately directing how poulations change over time
Domestication: Wild species traits selected that are often not advantageous in the wild
Ex) dog breeds, wheat

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9
Q

17

Population changes that’s NOT by natural selection

A

Genetic drift: population change by LUCK
- Certain individuals can’t reproduce suddenly due to luck.
- 갑자기 내가 파리채로 파란 파리들을 몰살하면 우짜것어
- MoRe likely to happen when the population is small

Genetic bottleneck: drift to the extreme!
- A sudden loss of population can dramatically change the traits and variation of a population.
- The survivors are the only contributors to the gene pool

Founder effect: Reverse bottleneck(?)
- A small population that moves into a new place is just a sample of the old population’s diversity

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10
Q

18

Species concept

A

What makes a species
- Its provides us ways to categorize life

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11
Q

18

Morphology

A

Using physical similarity/difference to delineate species
- colours/shape
- But it’s NOT a good and meaningful way

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12
Q

18

Biological species concept + criticism to this definition

definition of species + 4 criticisms

A

Species: a group of organisms that are capable of interbreeding, and can produce viable offspring that can also reproduce
Criticism:
1. Cannot be used to define asexual species
2. What we think are separate species might be able to reproduce by mating each other (라이거 같은)
3. Extinct groups are impossible to verify
4. Interbreeding populatins might display meaningful morphological differences (we might want to categorize them into different species)

1 way to define a species that works for all organisms doesn’t exist yet

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13
Q

18

Binomial species names + why name species this way?

2 reasons

A

Each species has 2 names:
Genus + Specific epithet

  1. Standardized, “universal” language between biologists
  2. Each organism can have only 1 binomial names but often have multiple common names that could cause confusion
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14
Q

18

Linnaean Classification System

A
  1. Domain
  2. Kingdom
  3. Phylum
  4. Class
  5. Order
  6. Family
  7. Genus
  8. Species
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15
Q

18

All species in a genus should share a____

A

Common ancestor
ex) all members of the ‘Canis’ genus share a common ancestor (dogs, coyote, wolves)

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16
Q

18

Key properties that separates 2 species

2

A
  1. Separate species should NOT be able to interbreed
  2. Populations that cannot interbreed are: reproductively isolated
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17
Q

18

Reproduction Isolation(barriers between species) can occur by:

3 cases - summary

A

1. Temproal Isolation
2. Habitat Isolation
3. Hybrids not being viable

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18
Q

18

2 Categories of reproductive isolation

A
  1. prezygotic isolation: individuals can’t physically meet and mate
  2. postzygotic isolation: individuals can mate, but the offsprings are inviable or infertile
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19
Q

18

Temporal Isolation

pre? post?

A

Species don’t interbreed because reproduction happens at different times
- Common in olants & insects
- Prezygotic isolation

20
Q

18

Habitat Isolation

A

Species do not interbreed because they occupy different habitats
- Prezygotic isolation

21
Q

18

Hybrid Inviability

A

Species can interbreed but the hybrid offsprings do not survive or offsprings are infertile
- Failure to survive to sexual maturity
- Embryonic development failure
- Postzygotic isolation

22
Q

18

When does a new species arise?

A
  1. species is evolving through time, capable of mating, enabling gene flow.
  2. barrier rises! Dividing the population
  3. Gene flow disrupted
  4. Changes accumulate that cause reproductive isolation
  5. New species emerge
23
Q

18

2 Types of Speciation

A
  1. Allpatric speciation
  2. Sympatric speciation
    -> Both of them are related to where the two species are when they diverge
24
Q

18

Why/When would gene stop flowing?

3 reasons

A
  1. Individuals will also not necessarily stay in teh same place
  2. The environments can suddenly change
  3. Randome chance and other processes can also eliminate portions of the population
25
# 18 Allopatric Speciation + 2 types
**Geographic separation** *physically* prevents species from interbreeding - Either species moving to isolated islands or the geological change separate the population 1. Vicariance: Water spliting land 2. Dispersal: new small island created next to the main land become bigger
26
# 18 Sympatric Speciation + Adaptive radiation
Sympatric Speciation: populations **not** physically isolated but an also result in speciation. - Diverging/Disruptive selection causes sympatri specition. - **Adaptive radiation:** when. founder population *colonizes a new area,* new species can rapidly emerge as the offspring begin settling into their own unique niche and diverging in characteristics from the original founder population. - This occurs when teh founder populations are *still in contact*
27
# 18 Hybrid zone
When imperfectly isolated species come into contact, the balance between **interbreeding** and **selection against hybrids** can maintain a **hybrid zone** - 2 opposite forces controlling the population of the interbreeding hybrids - That area is the hybrid zone - **Hybridization** could form new species - More likely in plants (orange + pomelo = grapefruit)
28
# 19 Ecology | Define it
Study of the interactions of living things with their environment. | at both single organism and ecosystem levels
29
# 19 Ecological Niche + 5 aspects of life history
Range of environmental conditions/resources a species can tolerate within its ecosystem - In a given ecosystem, each species settle into their unqiue ecological niche - Niches can change over time - The **life history** of a species can determine the niche Aspects of Life history: 1. Size of mature individual 2. Timing of maturity 3. Parental care 4. Offspring #: **Ferundity** 5. # of reproduction events in lifespan
30
# 19 Population ecology + important values of population ecology calculation
**Population ecology:** Concerns how *populations change over time in a given environment* - Measure changes in a population in response to biotic & abiotic factors. Some important values: 1. Population size 2. Density 3. Distribution
31
# 19 Models of Population growth | 4 variables
**N** = # of individuals in a population **t** = time span **r max** = the max growth rate of the population (Birth & death rate) - Life history determines this **K** = **Carrying Capacity** = the maximum population size that a given environment can sustain
32
# 19 2 Models used to generalize population changes
**Exponential growth model** - Population change if **resources** are **UNLIMITED** - a population will increase *consistently and indefinitely* **Logistic growth model** - Resources are **LIMITED** - There is **Carrying capacity** - The limit's impact increase as the N approaches K | These are theoretical though
33
# 19 2 other things that regulate population growth (that's not K) | Which one is abiotic and which one is biotic?
**Density dependent regulation:** - At high densities, there is more competition for limited resources - Disease spreads faster - Individuals are more easily preyed upon - **ALL BIOTIC FACTORS** **Density Independent regulation:** - Seasonal changes - Disasters - Regardless of how many species there are - **ALL ABIOTIC FACTORS**
34
# 19 r- vs K-selected species
**K-selected species:** - Staying close to K (maximize spending energy on fewer offsprings) - 질로 승부 **r-selected species:** - Maximize reproductive rate (r) - 양으로 승부
35
# 19 How to determine K?
We need to determine what the **limiting resources** are
36
# 20 Community Ecology + 3 types of symbiosis | Define it
**Community Ecology:** How species interact with each other 1. Competition 2. Consumption 3. Symbiosis
37
# 20 Competition - Competitive exclusion principle - Resource partitioning - What if the niche *completely overlap?* | Don't forget the +. - sign
When 2 species in a community can **use the same resources** (niches overlap) there is **competition** - Neither of the species benefit from this interaction (-, -) **Competitive Exclusion principle:** species can't occupy the same niche. **Resource Partitioning:** one or both species will *evolve* to modify niches until they no longer compete If niches completely overlap, one species could be **forced out** of the community or **extinct**
38
# 20 Consumption - Heterotrophic species? - Predation & Herbivory
* Nom nom food * (+,-) * **Predation:** Where an individual of one species KILLS and eats another for food * **Herbivory:** one species eats an **autotroph**
39
# 20 How predation & herbivory drive **evolutionary arms races** | 3 ways + how plants do it
Species selected for adaptations to avoid being eaten or consume food more effectively. 1. Camouflage / warning coloration -for both prey & predator 2. **Mimicry:** warning colouratin but animals piggyback on the true warnings of a different species Plants: - Being pointy - Poisonous - Caffeine - Etc
40
# 20 3 main types of symbiosis
1. Parasitism 2. Commensalism 3. Mutualism
41
# 20 Parasitism
Parasite species benefits but host **negatively affceted** - (+,-) (or +, 0) - A parasite usually takes *nutrients* from its host - Host could die but not necessarily (cuz then where would the parasite live)
42
# 20 Commensalism
1 species benefits while the relationship **remains neutral** for the other - (+, 0)
43
# 20 Mutualism
- BOTH BENEFIT - (+,+)
44
# 20 Red Queen hypothesis of evolution
A species **MUST adapt and evolve** not just for reproductive advantage, but also for **survival** because the **competing organisms are also evolving**
45
# 20 Community dynamics - Primary succession - Secondary succession (r- or k-selected species are more prevalent?)
Study of how community composition changes **Primary succession:** immediately after a disturbance, pioneer species adapted for the disturbed environment took over and formed a community **Secondary succession:** the community changes to different species to reach an *equilibrium state* of the area - r-selected species are more prevalent in that area cuz they reproduce quickly
46
# 20 Food chain & food web
**Food chain:** a linear network of links in a food web BUT Many organisms eat organisms from different **trophic levels** it's better to organize into **food web**

BIOL 111 (4 decks)

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